Variable capacitors are commonly used in electrical circuits such as a variable frequency oscillator, tuned amplifier, phase shifter, impedance-matching circuit and the like. A mechanically controlled variable capacitor typically includes an interelectrode spacing (or an electrode overlap area) between a pair of electrodes, which spacing can be controllably varied in order to selectively vary the capacitance between the electrodes. An electronically controlled variable capacitor relies on constantly applying a DC bias voltage to an element of the capacitor to change an electrical property of the element, thereby changing the capacitance as long as the bias voltage is applied. Conventionally, a silicon oxide (SiO2) thin film, a silicon nitride (Si3N4) thin film, and a tantalum oxide (Ta2O5) thin film have commonly been used for forming a thin film capacitor. A recent trend is to manufacture variable capacitors using Micro-Electro-Mechanical Systems (MEMS) technology. However, all of these approaches involve physically moving a portion of the capacitor and/or constantly applying a DC bias voltage in order to change the capacitance.